To all whom it may concern Be itknown that we, GOTTFRIED GRILL and JOHN BETZ, both of Baltimore city, State of Maryland, have invented certain new and useful Improvements in Key-Hole Guards; and we hereby declare the same to be fully, clearly, and exactly described as follows, reference being had to the accompanying drawings, in which- Figure 1 is a side elevation of a lock-case having our improvement, and Fig. 2 is a similar view of the inside of the case.

Our invention has for its object to provide a key-hole guard adapted to closethe slot below the shaft of the'key, and to defeat the removal of the key by an instrument inserted in the key-hole from the opposite side; and to this end we have devised a guard constructed and operating as hereinafter set forth.

In the drawings, A is the lock-case, having cast or formed on its face a pair of dovetail slides, a a.

B is a plate which fits between the slides, provided with a boss or knob, O, and projecting shell b, and having its corner 0 cut away, as shown, to fit around the projecting shank of the key when in place. The plate of the look is provided with the usual key-hole, D, and has a slot, E, through which projects a rivet or boss, 6. A spring, f, connects the boss 6 with a stud, F, on the lock-plate. The slot is made of such length that when the stud or boss 6 abuts against the end nearest the keyhole the shell b is exactly opposite the circular part of the key-hole, and permits the entrance of theshank of the key. When the stud is at the opposite end of the slot the key-hole is entirely uncovered.

To insert the key through the face of the lock, the plate B is moved by means of the knob O to the right (on Fig. 1) as far as it will go, when the key-hole is uncovered and the key may be inserted. On releasing the knob the plate slides back against the shank of the key, and the lower portion of the hole is covered. The key cannot now be pushed outof thelock from the opposite side. When the key is entirely removed the plate B slides to a position in which the shell I) .is opposite the circular part of the hole, and the entire key-holeis covered.

Instead of casting the slides upon the face of the lock, the plate B may be provided with one or more rivets sliding in slotsin the plate, whereby the same end will be attained.

e are aware that swinging or sliding guards to cover key-holes are not, broadly, new, and such we do not claim.

What we claim isk i 1. In a key-hole guard, a plate aflixed to the lock-case and having a recess to receive the shank of the key, a shell to receive the end of the key, and a projecting portion which covers the slot of the key-hole, as set forth.

2. In combination with the lock-plate having slides a, the plate YB, having shell I), and a spring, f, substantially as set forth. GOTTFRIED GRILL. JOHN BETZ. \Vitnesses: